The invention relates to a transport car with rollers, which may be steered. The rollers are mounted at two axles of the shopping cart, in order to ensure a tilt-safe movement of the shopping cart. The rollers are rotatable at the front axle around a steering axis aligned perpendicular to the direction of movement. At the rear axle, the rollers are either pivotal around a control axis similar to the rollers of the front axle or the rollers cannot be steered. The rollers of the rear axle, which cannot be steered, are know to those skilled in the art as “fixed rollers.”
The transport car with rollers that can be steered at the front and rear axles are easier to maneuver. In Europe, primarily transport cars of this type are used, in the U.S.A. primarily transport cars with fixed rollers are used.
Such transport cars are provided inside the market by shopping markets for customers to transport goods, and are also provided in a corresponding parking lot, if applicable.
In order to prevent a transport car from moving outside the permitted area a number of devices are known, which prevent the pushing of the transport car or at least make it substantially more difficult.
Some of the solutions provide for blocking at least one roller. These solutions can be used equally regardless of the type of rear axle used. In this solution it is disadvantageous for the rollers because they can become severely worn at one point and subsequently no longer roll smoothly.
Another solution provides for fixing a steering axle of one wheel of the front axle in a diagonal position in order to allow only a circular movement of the shopping cart. Although this prevents the unilateral wear it is only effective in transportation rollers with fixed rollers at the rear axle, the so-called fixed rollers.